Michael Martin's chapter in his "Atheism: A Philosophical Justification" reviews some of the many problems of omnipotence associated with the God of Classical Theism. But to be fair, the cartoon makes reference to one of the alleged sayings of Jesus in the New Testament Gospels. If Jesus was not God, did not exist, or did not say the faith as a mustard seed pericope, then that part of the challenge fails. Failure to answer prayers for overt miracles, whack comedians, or filter out religious charlatans isn't evidence for non-existence of GCT either unless there is some reason to think these sorts of actions would be what is expected from GCT if it did exist. However, as the purported attributes of GCT are known from the alleged revealed religions, then this is a matter of reliability of the books of religious fairy tales. To the best understanding I have, it is the case that none of the religious fairy tales stand up to critical examination. Therefore the alleged attributes of GCT are not actually known, and so GCT cannot be argued against on the basis that reality falsifies its attributes. Thinkers are then left in a position of brutal agnosticism unless there is a way to rule out beings of pure consciousness or that are transcendent or infinite in scope. I think there are such ways, and that therefore positive disbelief is justifiable.